Rather than using hydrogen to power fuel cells and the associated high-pressure storage problems associated with this, we could would use water to produce hydrogen from electrolysis, and this is then combined with nitrogen from the air to produce ammonia.

The ammonia itself would then be burned in an internal combustion engine, but the burning process only releases water vapor and nitrogen, rather than the unburned hydrocarbons and other pollutants that internal combustion is normally associated with.

In theory, the ammonia is also simple and cheap to produce — enough so that it could be sold at 20 cents per gallon. As long as researchers keep working on radical ideas such as Ammonia powered cars or "urine powered cars", they are bound to one day to hit on the formula that can be widely adopted.